Onconase is one kind of ribonucleases in ova or early embryos of Rana pipiens. It comprises 104 amino acid residues and has a molecular weight of about 12,000 daltons. Onconase is a member of RNase A (Bovine pancreatic ribonuclease A) super family. Onconase has a 30% identity to RNase A in primary structure and both of them have a quite similar tertiary structure. Onconase can inhibit growth of various tumors. Although Onconase is a protein drug, it is low immunogenic so that it is clinically suitable for multiple courses of treatment. It can counteract the multiple drug resistance and has few side effects.
Artemisinin was invented and developed as a novel anti-malaria drug by Chinese scientists. Considering the common drug resistance of quinine drugs, artemisinin and derivatives thereof have replaced them and become main drugs for anti-malaria over the world. Artemisinin is a sesquiterpene lactone compound extracted from leaves of artemisia annua, which is a Chinese medicinal plant. The Endoperoxide Bridge in the macro-ring of artemisinin releases carbon-centered free radicals under ferrous iron and ferroheme catalysis. The cells may die after alkylation of intracellular protein and nuclear acid caused by these free radicals. The plasmodia parasitizing in red blood cells contain a large amount of ferroheme derived from hemoglobin so that artemisinin is easily activated and kill plasmodia. Artemisinin or derivatives thereof, such as dihydroartemisinin, artemether, arteether, and artesunate etc., have already been widely used for malaria treatments. More artemisinin derivatives are under development. Scientists in China and overseas have found out that artemisinin has an antitumor effect in recent years. Artemisinin or the derivatives thereof presents a broad-spectrum antitumor effect.
However, it is unknown in the art about the effect of combination of these two unique drugs of ribonuclease and artemisinin for tumor treatments. Such a problem is eagerly to be solved in the field.